Hand-held power tool as well as axial holding arrangement and working element for such a power tool

Abstract

The invention refers to hand-held power tool ( 10 ) comprising a tool housing ( 12 ), a motor ( 24 ) and a tool shaft ( 36 ) having a rotational axis ( 40 ) and actuated by the motor ( 24 ), and further comprising a working element ( 38 ) releasably attachable to the tool shaft ( 36 ) from outside the tool housing ( 12 ) in an axial direction and, after attachment to the tool shaft ( 36 ), held in respect to the tool shaft ( 36 ) by means of an axial holding arrangement ( 80 ). The axial holding arrangement ( 80 ) comprises a first element ( 36; 38 ) constituted by one of the working element ( 38 ) and the tool shaft ( 36 ) and a second element ( 38; 36 ) constituted by the other one of the working element ( 38 ) and the tool shaft ( 36 ), and at least two locking elements ( 70 ) assigned to the first element ( 36; 38 ) movably in a radial direction between a retracted position and a locking position, at least one recess ( 66 ) assigned to the second element ( 38; 36 ) for receiving the locking elements ( 70 ) when in their locking positions. The locking elements ( 70 ) or the second element ( 38; 36 ) in and/or around the at least one radial recess ( 66 ) comprises a magnetic material and the at least other one of the locking elements ( 70 ) and the second element ( 38; 36 ) in and/or around the at least one radial recess ( 66 ) comprises a magnetic material or a ferromagnetic material. The locking elements ( 70 ) are automatically moved into and held in their locking positions and in the at least one radial recess ( 66 ) by means of magnetic force after attachment of the working element ( 38 ) to the tool shaft ( 36 ).

The invention claimed is: 
     
       1. A hand-held power tool ( 10 ) comprising a tool housing ( 12 ) and a motor ( 24 ) located therein and a tool shaft ( 36 ) having a rotational axis ( 40 ) and actuated by the motor ( 24 ) when in operation in order to make the tool shaft ( 36 ) perform a rotational movement about its rotational axis ( 40 ), a distal end of the tool shaft ( 36 ) being accessible from outside the tool housing ( 12 ), and further comprising a working element ( 38 ) releasably attachable to the distal end of the tool shaft ( 36 ) from outside the tool housing ( 12 ) in an axial direction extending parallel to the rotational axis ( 40 ) of the tool shaft ( 36 ) and, after attachment to the tool shaft ( 36 ), held in respect to the tool shaft ( 36 ) by means of an axial holding arrangement ( 80 ),
 characterized in that the axial holding arrangement ( 80 ) comprises: 
 a first element ( 36 ;  38 ) constituted by one of the following elements, the working element ( 38 ) and the tool shaft ( 36 ), and a second element ( 38 ;  36 ) constituted by the other one of the elements, the working element ( 38 ) and the tool shaft ( 36 ), and 
 at least one locking element ( 70 ) assigned to the first element ( 36 ;  38 ) movably in a radial direction between a retracted position, in which the at least one locking element ( 70 ) is retracted in the first element ( 36 ;  38 ), and a locking position, in which the at least one locking element ( 70 ) protrudes from the first element ( 36 ;  38 ) radially towards the second element ( 38 ;  36 ), 
 at least one radial recess ( 66 ) assigned to the second element ( 38 ;  36 ) and having a radial extension, the at least one radial recess ( 66 ) being configured to receive part of the at least one locking element ( 70 ) when in its locking position after attachment of the working element ( 38 ) to the tool shaft ( 36 ), 
 wherein at least one of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) in, around, or in and around the at least one radial recess ( 66 ), comprises a magnetic material, 
 at least one other of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) comprises the magnetic material or a ferromagnetic material, 
 so that the at least one locking element ( 70 ) is automatically moved into and held in its locking position and in the at least one radial recess ( 66 ) by means of magnetic force after attachment of the working element ( 38 ) to the tool shaft ( 36 ), thereby engaging with the at least one radial recess ( 66 ) and holding the working element ( 38 ) in respect to the tool shaft ( 36 ) in the axial direction. 
 
     
     
       2. The hand-held power tool ( 10 ) according to  claim 1 , wherein the first element is the tool shaft ( 36 ) and the second element is the working element ( 38 ). 
     
     
       3. The hand-held power tool ( 10 ) according to  claim 2 , wherein the first element ( 36 ;  38 ) has an axial bore ( 68 ) and the at least one locking element ( 70 ) is held in a hollow cylindrical jacket ( 78 ) radially delimiting the axial bore ( 68 ). 
     
     
       4. The hand-held power tool ( 10 ) according to  claim 3 , wherein the second element ( 38 ;  36 ) has a cylindrical pin ( 58 ;  64 ) and the at least one radial recess ( 66 ) is provided on an external circumferential surface of the cylindrical pin ( 58 ;  64 ). 
     
     
       5. The hand-held power tool ( 10 ) according to  claim 4 , wherein either a distal end ( 82 ) of the cylindrical pin ( 58 ;  64 ) or an outer edge ( 96 ) delimiting an entry hole into the axial bore ( 68 ) has, or both the distal end ( 82 ) and the outer edge ( 96 ) have, a tapered or rounded form in order to facilitate insertion of the cylindrical pin ( 58 ;  64 ) into the axial bore ( 68 ) and to automatically push the at least one locking element ( 70 ) in a radial direction into its retracted position during insertion of the cylindrical pin ( 58 ;  64 ) into the axial bore ( 68 ). 
     
     
       6. The hand-held power tool ( 10 ) according to  claim 4 , wherein the axial bore ( 68 ) and the cylindrical pin ( 58 ;  64 ) each having an axially extending section ( 84 ) with a corresponding cross-sectional surface without rotational symmetry and being configured to mechanically engage with each other after attachment of the working element ( 38 ) to the tool shaft ( 36 ), thereby permitting the transmission of torque from the tool shaft ( 36 ) to the working element ( 38 ) during operation of the motor ( 24 ) of the power tool ( 10 ). 
     
     
       7. The hand-held power tool ( 10 ) according to  claim 2 , wherein the first element ( 36 ;  38 ) has a cylindrical pin ( 58 ;  64 ) and the at least one locking element ( 70 ) is held in an external circumferential surface of the cylindrical pin ( 58 ;  64 ). 
     
     
       8. The hand-held power tool ( 10 ) according to  claim 7 , wherein the second element ( 38 ;  36 ) has an axial bore ( 68 ) and the at least one radial recess ( 66 ) is provided on an internal circumferential surface of a hollow cylindrical jacket ( 78 ) radially delimiting the axial bore ( 68 ). 
     
     
       9. The hand-held power tool ( 10 ) according to  claim 8 , wherein either a distal end ( 82 ) of the cylindrical pin ( 58 ;  64 ) or an outer edge ( 96 ) delimiting an entry hole into the axial bore ( 68 ) has, or both the distal end ( 82 ) and the outer edge ( 96 ) have, a tapered or rounded form in order to facilitate insertion of the cylindrical pin ( 58 ;  64 ) into the axial bore ( 68 ) and to automatically push the at least one locking element ( 70 ) in a radial direction into its retracted position during insertion of the cylindrical pin ( 58 ;  64 ) into the axial bore ( 68 ). 
     
     
       10. The hand-held power tool ( 10 ) according to  claim 8 , wherein the axial bore ( 68 ) and the cylindrical pin ( 58 ;  64 ) each having an axially extending section ( 84 ) with a corresponding cross-sectional surface without rotational symmetry and being configured to mechanically engage with each other after attachment of the working element ( 38 ) to the tool shaft ( 36 ), thereby permitting the transmission of torque from the tool shaft ( 36 ) to the working element ( 38 ) during operation of the motor ( 24 ) of the power tool ( 10 ). 
     
     
       11. The hand-held power tool ( 10 ) according to  claim 1 , wherein the first element is the working element ( 38 ) and the second element is the tool shaft ( 36 ). 
     
     
       12. The hand-held power tool ( 10 ) according to  claim 11 , wherein the first element ( 36 ;  38 ) has an axial bore ( 68 ) and the at least one locking element ( 70 ) is held in a hollow cylindrical jacket ( 78 ) radially delimiting the bore ( 68 ). 
     
     
       13. The hand-held power tool ( 10 ) according to  claim 11 , wherein the first element ( 36 ;  38 ) has a cylindrical pin ( 58 ;  64 ) and the at least one locking element ( 70 ) is held in an external circumferential surface of the cylindrical pin ( 58 ;  64 ). 
     
     
       14. The hand-held power tool ( 10 ) according to  claim 1  wherein either a distal end surface ( 74 ) of the at least one locking element ( 70 ) facing the second element ( 38 ;  36 ) after attachment of the working element ( 38 ) to the tool shaft ( 36 ), or an outer edge ( 94 ) delimiting an entry hole into the at least one radial recess ( 66 ) facing the first element ( 36 ;  38 ) after attachment of the working element ( 38 ) to the tool shaft ( 36 ) has, or both the distal end surface ( 74 ) and the outer edge ( 94 ) have, a tapered or rounded form ( 76 ) in order to facilitate automatically pushing the at least one locking element ( 70 ) in a radial direction into its retracted position during detachment of the working element ( 38 ) from the tool shaft ( 36 ). 
     
     
       15. The hand-held power tool ( 10 ) according to  claim 1 , wherein the at least one locking element ( 70 ) and the at least one radial recess ( 66 ) are correspondingly shaped to engage with each other in the locking position of the at least one locking element ( 70 ). 
     
     
       16. The hand-held power tool ( 10 ) according to  claim 1 , wherein the working element ( 38 ) comprises an eccentric element ( 54 ) which is releasably attached to the tool shaft ( 36 ) in the axial direction, and a backing pad ( 48 ) attached to a side of the eccentric element ( 54 ) opposite to the tool shaft ( 36 ) in a manner freely rotatable about a second rotational axis ( 60 ) of the backing pad ( 48 ), the second rotational axis ( 60 ) extending parallel in respect to the rotational axis ( 40 ) of the tool shaft ( 36 ) and in a distance thereto, or wherein the working element ( 38 ) comprises a backing pad ( 48 ) which is releasably attached to the tool shaft ( 36 ) in the axial direction. 
     
     
       17. The hand-held power tool ( 10 ) according to  claim 1 , wherein
 at least two locking elements ( 70 ) are equidistantly positioned in a circumferential direction about the rotational axis ( 40 ) of the tool shaft ( 36 ) after attachment of the working element ( 38 ) to the tool shaft ( 36 ), or 
 the axial holding arrangement ( 80 ) comprises at least three locking elements ( 70 ), or 
 the at least two locking elements ( 70 ) are equidistantly positioned in the circumferential direction about the rotational axis ( 40 ) of the tool shaft ( 36 ) after attachment of the working element ( 38 ) to the tool shaft ( 36 ) and the axial holding arrangement ( 80 ) comprises the at least three locking elements ( 70 ). 
 
     
     
       18. The hand-held power tool ( 10 ) according to  claim 1 , wherein the axial holding arrangement ( 80 ) comprises the same number of one or more radial recesses ( 66 ) as there are locking elements ( 70 ) provided in the axial holding arrangement ( 80 ), or wherein the axial holding arrangement ( 80 ) comprises a single annularly shaped radial recess ( 66 ) configured to receive one locking element ( 70 ) or all of the locking elements ( 70 ) in their locking positions. 
     
     
       19. An axial holding arrangement ( 80 ) for holding a working element ( 38 ) of a hand-held power tool ( 10 ) in respect to a tool shaft ( 36 ) of the power tool ( 10 ) in an axial direction extending parallel to a rotational axis ( 40 ) of the tool shaft ( 36 ), after releasable attachment of the working element ( 38 ) to a distal end of the tool shaft ( 36 ) in the axial direction,
 characterized in that the axial holding arrangement ( 80 ) comprises 
 a first element ( 36 ;  38 ) constituted by one of the following elements, the working element ( 38 ) and the tool shaft ( 36 ), and a second element ( 38 ;  36 ) constituted by the other one of the elements, the working element ( 38 ) and the tool shaft ( 36 ), and 
 at least one locking element ( 70 ) assigned to the first element ( 36 ;  38 ) movably in a radial direction between a retracted position, in which the at least one locking element ( 70 ) is retracted in the first element ( 36 ;  38 ), and a locking position, in which the at least one locking element ( 70 ) protrudes from the first element ( 36 ;  38 ) radially towards the second element ( 38 ;  36 ), 
 at least one radial recess ( 66 ) assigned to the second element ( 38 ;  36 ), the at least one radial recess ( 66 ) being configured to receive part of the at least one locking element ( 70 ) when in its locking position and after attachment of the working element ( 38 ) to the tool shaft ( 36 ), 
 wherein at least one of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) in, or around, or in and around the at least one radial recess ( 66 ), comprises a magnetic material, and 
 at least one other of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) comprises the magnetic material or a ferromagnetic material, 
 so that the at least one locking element ( 70 ) is automatically moved into and held in its locking position and in the at least one radial recess ( 66 ) by means of magnetic force after attachment of the working element ( 38 ) to the tool shaft ( 36 ), thereby engaging with the at least one radial recess ( 66 ) and holding the working element ( 38 ) in respect to the tool shaft ( 36 ) in the axial direction. 
 
     
     
       20. A working element ( 38 ) of a hand-held power tool ( 10 ), configured for releasable attachment to a distal end of a tool shaft ( 36 ) of the power tool ( 10 ) in an axial direction extending parallel to a rotational axis ( 40 ) of the tool shaft ( 36 ) and further configured to be held in respect to the tool shaft ( 36 ) in the axial direction by means of an axial holding arrangement ( 80 ), after attachment of the working element ( 38 ) to the tool shaft ( 36 ) in the axial direction,
 characterized in that 
 the working element ( 38 ) comprises a first element, wherein a second element makes part of the tool shaft ( 36 ), or the working element ( 38 ) comprises a second element, wherein a first element makes part of the tool shaft ( 36 ), and 
 if the working element ( 38 ) is the first element, at least one locking element ( 70 ) is assigned to the working element ( 38 ) movably in a radial direction between a retracted position, in which the at least one locking element ( 70 ) is retracted in the working element ( 38 ), and a locking position, in which the at least one locking element ( 70 ) protrudes from the working element ( 38 ) radially towards the tool shaft ( 36 ), wherein at least one radial recess ( 66 ) is assigned to the tool shaft ( 36 ), the at least one radial recess ( 66 ) being configured to receive part of the at least one locking element ( 70 ), when in its locking position and after attachment of the working element ( 38 ) to the tool shaft ( 36 ), or 
 if the working element ( 38 ) is the second element, at least one radial recess ( 66 ) is assigned to the working element ( 38 ), the at least one radial recess ( 66 ) being configured to receive part of the at least one locking element ( 70 ), wherein the at least one locking element ( 70 ) is assigned to the tool shaft ( 36 ) movably in a radial direction between a retracted position, in which the at least one locking element ( 70 ) is retracted in the tool shaft ( 36 ), and a locking position, in which the at least one locking element ( 70 ) protrudes from the tool shaft ( 36 ) radially towards the working element ( 38 ), when the at least one locking element ( 70 ) is in its locking position and after attachment of the working element ( 38 ) to the tool shaft ( 36 ), 
 wherein at least one of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) in, or around, or in and around the at least one radial recess ( 66 ), comprises a magnetic material, and 
 at least one other of the at least one locking element ( 70 ) and the second element ( 38 ;  36 ) comprises the magnetic material or a ferromagnetic material, 
 so that the at least one locking element ( 70 ) is automatically moved into and held in its locking position and in the at least one radial recess ( 66 ) by means of magnetic force after attachment of the working element ( 38 ) to the tool shaft ( 36 ), thereby engaging with the at least one radial recess ( 66 ) and holding the working element ( 38 ) in respect to the tool shaft ( 36 ) in the axial direction. 
 
     
     
       21. The working element ( 38 ) according to  claim 20 , wherein the working element ( 38 ) comprises an eccentric element ( 54 ) which is releasably attachable to the tool shaft ( 36 ) in the axial direction, and a backing pad ( 48 ) attached to a side of the eccentric element ( 54 ) opposite to the tool shaft ( 36 ) in a manner freely rotatable about a second rotational axis ( 60 ) of the backing pad ( 48 ), the second rotational axis ( 60 ) extending parallel in respect to the rotational axis ( 40 ) of the tool shaft ( 36 ) and in a distance thereto, or wherein the working element ( 38 ) comprises a backing pad ( 48 ) which is releasably attachable to the tool shaft ( 36 ) in the axial direction.